Electric furnace



Patented Sept. 29, 1925.

UNITED STATES PATENT OFFICE.

ALVIN D. KEENE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNO'R TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC FURNACE.

Application filed August 18, 1923.

To all whom it may concern:

Be it known that I, ALVIN D. KEENE, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electr c Furnaces, of which the following is a specification.

My invention relates to electric furnaces and particularly to electric resistor furnaces.

The object of my invention is to provide a relatively simple resistor mounting for an electric resistor furnace that shall permit of being easily placed in, and removed from, the furnace structure.

In practicing my invention, I provide a plurality of refractory heat-insulating walls enclosing a furnace chamber and supporting a plurality of spaced sets of refractory members, of substantially T-shape, pro ecting into the furnace chamber. The refractory members of T-shape are spaced apart in each set and each member is provided with a depression in one surface adjacent to the inner end thereof, and is provided in the other surface thereof With alongitudinally extending groove.

Relatively narrow and thin refractory plates, having laterally extending grooves in their inner surface, are held by adjacent members of Tsl1ape, the ends of the grooved bars fitting into a depression and a groove respectively.

A relatively heavy resistor member preformed to comprise a plurality of straight, substantially parallel-extending end connected convolutions is held by the grooved plates whereby the convolutions extend substantially parallel to the furnace walls and closely adjacent thereto. The resistor member is substantially self-supporting between and beyond the refractory grooved supporting plates or bars.

The device embodying my invention is closely related to and is an improvement upon the device disclosed ina co-pending application of T. A. Reid, Serial No. 584,620, filed August 28th, 1922, and assigned to the lVestinghouse Electric & Manufacturing Company.

In the single sheet of drawings Figure 1 is a View, in vertical lateral sec- Serial No. 658,032.

tion, of an electric furnace embodying my invention,

Fig. 2 is a view in front elevation of the device embodying my invention, and

Fig. 3 is a view, partly in side elevation and partly in section, of the device illustrated in Fig. 2.

An electric furnace 11 comprises side Walls 12, a bottom wall 13 and a top wall 141, each of which is constituted by a plurality of refractory bricks or blocks of suitable heat-insulating material.

An inner lining 15 for each of the walls may comp-rise a plurality of bricks or blocks of suitable refractory high-temperature resisting material, the hereinbefore described walls being suitably spaced apart to provide a furnace chamber 16 of any suitable or desired contour and dimensions.

I11 building up the inner layer 15 in the side end and top walls, a plurality of sets of elongated refractory supporting members 17 are located therein, symmetrically spaced both laterally and longitudinally of the supporting wall. Each of the members 17 extends a short distance into the furnace cham ber 16 and is provided in one of its surfaces adjacent to the inner end thereof with a depression 18.

A longitudinallyextending slot or groove 19 is provided in the opposite surface of the members 17 adjacent to the inner ends thereof of the member 17. The location of the groove and of the depression is such as to permit of locating therein the respective ends of a relatively narrow, elongated bar 21 which consists of a suitable refractory electric-insulating material.

A resistor member 22 comprises a plurality of integral, end-connected, substantially parallel-extending, straight convolutions of a suitable metallic resistance material, a portion of each convolution being located in laterally-extending grooves 23 provided in the bars 21. The convolutions of the resistor member 22 extend between and beyond the spaced bars 21 and are located parallel and closely adjacent to the inner surface of the lining 15 of the respective walls.

Any desired terminal construction may be employed for the individual resistor members 22, of which a plurality may be provided as may be desired or as may be found necessary, and such terminal construction is not illustrated or described in detail, as it forms no part of my invention.

In installing the resistor members 22, they may be held in substantially their proper operative positions against or cloosely adjacent to the walls, after which the bars 21 may be suitably placed in their proper operative position by first moving that end there of that is to be located in a depression 18 so that this end will fit into the depression, while the other end thereof is located at a greater distance from the wall. By a lateral tiltin movement of the res )ective bars 21, relatively to the co-opera'ting wall, they are then moved into their proper operative positions substantially as illustrated in Figs. 1 and 3 of the drawing, it being understood, of course, that the respective convolutions of the resistor members 22 are placed in the co-operating grooves 23 whereby the convolutions are supported at spaced intervals. As above stated, the resistor member 22 is made up of relatively heavy resistor material that is substantially self-supporting between and beyond the bars 21.

A lock or key 24f is provided in the groove 10 in front of the outer surface of the bar 21 to prevent any lateral movement of the bars relatively to the adjacent walls surface. While this key member 2% has been shown as of substantially U-shape, it 'may be of L-shape, or other suitable shape, if desired.

Instead of providing a depression in one surface of each of the members 17 and a groove in the other surface thereof, I may provide a depression in each surface, one of the depressions being deeper than the other. The ends of the respective bars 21 [it into the depressions in the co-operating pairs of spaced members 17. One end of the bar 21 is placed into the deeper depression, and the bar is movedlongitudinally of its length until it touches the bottom of the depression and the other end is then given a lateral movement until it can be dropped into the shallower depression. No locking key is required and thebars 21 interlocked with the members 17 are held against a lateral movement eitherparallel to the face of the furnace wall or at right ang'les'thereto. The bars can be removed by a longitudinal and then a lateral tilting movement thereof.

in removing a damaged resistor, it is only necessary to remove the necessary number of key members 241, after which the bars 21 may be given a lateral tilting movement away from the adjacent wall. The free resistor unit 22, which was supported by these bars 21 may then be easily and quickly removed from the furnace structure and be replaced by a new heating unit.

Various modifications and changes may be made herein without departing from the spirit and scope of my invention, and I desire, therefore, that only such limitations shall be imposed as are set forth in the prior art or in the appended claims.

I claim as my invention:

1. In an electric furnace, in combination, a plurality of refractory walls enclosing a furnace chamber, a plurality of spaced sets of refractory members supported by one of said walls and having their inner ends projecting into said furnace chamber, the members of each set being located in aligned spaced relation relatively to each other, grooved resistorsupporting bars of refractory electricinsulating material extending between adjacent pairs of refractory members in each set and being placeable in operative ,position relatively thereto by a lateral tilting movement thereof, a resistor member of relatively heavy and unyielding material supported by said grooved bars and extending between and beyond said bars, and means on one of said refractory members for holding a bar in its proper operative position.

'2. In an electric furnace, in combination, a plurality of refractory walls enclosing a furnacechamber, a pluralityof refractory members supported by one of said Walls and projecting into said chamber, each member having a depression in one surface and a longitudinally-extending I open. groove in the opposite surface, a laterally grooved resistor-supporting bar extending between said refractory members and having its ends located respectively in said depression and said groove, and means operatively engaging one of said refractory members for holding said bar in its proper operative position.

3. In an electric furnace, in combination, a plurality of refractory walls enclosing a furnace chamber, 'a plurality of spacedrefractory members supported by one of said walls and having their innerends projecting into said chamber, and a resistorsupporting bar extending between said refractory members and interlocked therewith to ,prevent movementthereof parallel-to the refractory wall and being placed inoperative position relatively thereto by a tilting and lateral movement thereof.

In -testimony whereof, I havehereunto subscribed my name this 13th 'day of August, 1923.

ALVIN D. :KEENE. 

